• Journal of Microbiology and Biotechnology
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• v.33 no.2
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• pp.188-194
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• 2023

Microbacterium elymi KUDC0405^T was isolated from the rhizosphere of Elymus tsukushiensis from the Dokdo Islands. The KUDC0405^T strain was Gram-stain-positive, non-spore forming, non-motile, and facultatively anaerobic bacteria. Strain KUDC0405^T was a rod-shaped bacterium with size dimensions of 0.3-0.4 × 0.7-0.8 ㎛. Based on 16S rRNA gene sequences, KUDC0405^T was most closely related to Microbacterium bovistercoris NEAU-LLE^T (97.8%) and Microbacterium pseudoresistens CC-5209^T (97.6%). The dDDH (digital DNA-DNA hybridization) values between KUDC0405^T and M. bovistercoris NEAU-LLE^T and M. pseudoresistens CC-5209^T were below 17.3% and 17.5%, respectively. The ANI (average nucleotide identity) values among strains KUDC0405^T, M. bovistercoris NEAU-LLE^T, and M. pseudoresistens CC-5209^T were 86.6% and 80.7%, respectively. The AAI (average amino acid identity) values were 64.66% and 64.97%, respectively, between KUDC0405^T and its closest related type strains. The genome contained 3,596 CDCs, three rRNAs, 46 tRNAs, and three non-coding RNAs (ncRNAs). The genomic DNA GC content was 70.4%. The polar lipids included diphosphatydilglycerol, glycolipid, phosphatydilglycerol, and unknown phospholipid, and the major fatty acids were anteiso-C_17:0 and iso-C_16:0. Strain KUDC0405^T contained MK-12 as the major menaquinone. Based on genotypic, phylogenetic, and phenotypic properties, strain KUDC0405^T should be considered a novel species within the genus Microbacterium, for which we propose the name M. elymi sp. nov., and the type strain as KUDC0405^T (=KCTC 49411^T, =CGMCC1.18472^T).

• Korean Journal of Soil Science and Fertilizer
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• v.23 no.1
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• pp.53-59
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• 1990

The antagonistic fluorescent pseudomonas, which was isolated from continuous cropping rhizosphere of pepper and cucumber, was identified as Pseudomonas fluorescens (P.f.). For further study, transformant was derived from the isolated P.f. after spontaneous mutation to give antibiotic resistance to nalidixic acid and rifampicin as marked strain. Both P.f. and transformant strains were used for this study and the results obtained were summarized as follows. 1. One of the most effective antagonistic strain, KR164, was selected against F. solani, F. oxysporum, R. solani and this strain was identified and classified as Pseudomonas fluorescens biotype IV. 2. Transformant, KR1641, was derived from strain KR164 and both strains had the same biological and biochemical characteristics. 3, Mycelial lysis and abnormal mycelia of plant pathogenic fungi were microscopically observed after simultaneous culture of fungus and given bacterial strain. 4. The length of chinese cabbage to the autolyzed became longer with given bacterial strain in dark culture. 5. Percentage of germination, number of leaves, length of height, and length of root in chinese cabbage in pot experiment were improved by inoculation of given bacterial strain. 6. The number of given bacterial strain kept generally stable until 34 days after inoculation of itself in pot experiment. Inoculation of given bacterial strain did affect the number of plant disease fungi to be decreased but did not affect the number of other bacteria, Bacillus, in pot experiment.

• Korean Journal of Environmental Biology
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• v.29 no.1
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• pp.52-60
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• 2011

Today, the weather is changing continually, due to the progress of global warming. As the weather changes, the habitats of different organisms will change as well. It cannot be predicted whether or not the weather will change with each passing day. In particular, the biological distribution of the areas climate change affects constitutes a major factor in determining the natural state of indigenous plants; additionally, plants are constantly exposed to rhizospheric microorganisms, which are bound to be sensitive to these changes. Interest has grown in the relationship between plants and rhizopheric microorganisms. As a result of this interest we elected to research and experiment further. We researched the dominant changes that occur between plants and rhizospheric organisms due to global warming. First, we used temperature as a variable. We employed four different temperatures and four different sites: room temperature ($27^{\circ}C$), $+2^{\circ}C$, $+4^{\circ}C$, and $+6^{\circ}C$. The four different sites we used were populated by the following species: Pinus deniflora, Pinus koraiensis, Quercus acutissima, and Alnus japonica. We counted colonies of these plants and divided them. Then, using 16S rRNA analysis we identified the microorganisms. In conclusion, we identified the following genera, which were as follows: 10 species of Bacillus, 2 Enterobacter species, 4 Pseudomonas species, 1 Arthrobacter species, 1 Chryseobacterium species, and 1 Rhodococcus species. Among these genera, the dominant species in Pinus deniflora was discovered in the same genus, but a different species dominated at $33^{\circ}C$. Additionally, that of Pinus koraiensis changed in both genus and species which changed into the Chryseobacrterium genus from the Bacilus genus at $33^{\circ}C$.

• Korean Journal of Environment and Ecology
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• v.24 no.3
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• pp.249-257
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• 2010

The purpose of this paper is to weigh the possibility of endangered Jang-hang wetland at the estuary of Han River to be included on the Ramsar List of Wetlands of International Importance and come up with ways to manage the wetland depending on its biotope patterns. The target area is located between Gimpo bridge and Isanpo I.C. with about $2.7km^2$ area. Through the analysis of RIS(Information Sheet for Ramsar Wetlands), it was known that the wetland is located on the sedimentary topography and formed as a result of sediment at the estuary of the river owing to the concentration of rainfall during summer. The vegetation environment in the area is divided into brackish water and fresh water areas depending on salinity. Rhizosphere soil(RS) of the area was analyzed to be Silt loam while bottom RS to be Sand loam. The plant ecology was composed of 52 families 135 species and 11 varieties and 146 types. Among indigenous species found are Salix koreensis, Phragmites communis and Miscanthus sacchariflorus. The analyzed results of the actual vegetation showed that willow community accounts for 37% of the area and rice field is 13.5%. As for animal ecology, total of 62 species and 25,977 individual wild birds were observed. After comparing and analyzing the RIS we compiled with the Ramsar Site designation standards, it turns out that the Jang-hang wetland meets criteria 1(biographic region), criteria 2,3 and 4(species and ecological communities) and criteria 5 and 6(water birds). Thus, Jang-hang wetland is eligible for the Ramsar site. As a result of establishing and evaluating the biotope types for setting management areas, Jang-hang wetland has a total of 13 different types, and the grade I represents 75.4% of the area while the grade III 0.8% of the land status. We categorized four management zones for the wetland depending on the biotope patterns - preservation, restoration, use and buffer zones and suggested management methods for each zone.

• Journal of Life Science
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• v.20 no.8
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• pp.1254-1260
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• 2010

Microorganisms near the plant rhizosphere usually inhabit the surface or the inside of the plant roots and have a direct effect on plant growth by secreting plant growth promoters or antagonistic materials which protect the root zone system from various pathogens. This study was carried out to identify and isolate the antagonistic materials after isolation of microorganisms showing high antagonistic activities, in hopes of contributing to the development of sustainable agriculture and the preservation of agricultural environments. A number of antagonistic bacteria were isolated from paddy soil. Among isolates, RRj 228 showed plant growth promotion and antagonistic activity. RRj 228 was identified as Pseudomonas sp. according to the results of physiological properties and genetic methods. On the basis of the results of anti-fungal spectrum against several pathogens by RRj 228, the antagonistic effect of the isolate against Botrytis cinerea, Pythium ultimum, Phytopthola capsici, and Rhizoctonia solani, especially against red-pepper anthracnose caused by Colletotrichum acutatum, was remarkable. The experiment evaluating the biological control effect by RRj 228 revealed that the $ED_{50}$ value by the RRj 228 culture against C. acutatum, R. solani and P. ultimum were 0.14 mg/ml, 0.16 mg/ml and 0.29 mg/ml, respectively. An antagonistic substance was isolated and purified by several chromatographies from the RRj 228 culture. The $^1H$ and $^{13}C$ assignment of the antagonistic substance was achieved from two-dimensional $^1H-^1H$ COSY, HMQC, and HMBC. Finally, the antagonistic substance was identified as Phenazine-1-carboxylic acid ($C_{13}H_8N_2O_2$, M.W.=224).

• Korean Journal of Microbiology
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• v.40 no.4
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• pp.342-347
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• 2004

A bacterial strain YC4963 with antifungal activity against Colletotrichum orbiculare, a causal organism of cucumber anthracnose was isolated from the rhizosphere soil of Siegesbeckia pubescens Makino in Korea. Based on physiological and biochemical characteristics and 16S ribosomal DNA sequence analysis, the bac­terial strain was identified as Pseudomonas aurantiaca. The bacteria also inhibited mycelial growth of several plant fungal pathogens such as Botrytis cinerea, Fusarium oxysporum and Rhizoctonia solani on PDA and 0.1 TSA media. The antifungal activity was found from the culture filtrate of this isolate and the active compound was quantitatively bound to XAD adsorption resin. The antibiotic compound was purified and identified as phenazine-l-carboxylic acid on the basis of combined spectral and chemical analyses data. This is the first report on the production of phenazine-l-carboxylic acid by Pseudomonas aurantiaca.